1956: Little-known computer creates vast legacy

• A U.S. district court makes a final judgment on a 1952 complaint against IBM regarding monopolistic practices. The company signs a consent decree that places limitations on the way it conducts business with respect to "electronic data processing machines," among other things. • The first trans-Atlantic telephone cable is developed. • Ampex Corp. perfects the first videotape recorder, which is rapidly adopted by the television industry because, unlike film, the electromagnetic tape requires no processing. • Thomas Watson Jr. becomes CEO of IBM. • IBM founder Thomas Watson Sr. dies. • Bell Labs develops prototype of the first picture phone. • Jay Forrester's patent is issued for magnetic core memory. • Noam Chomsky invents context-free grammar, which is used in nearly all programming languages after its initial use three years later to describe Algol 60.

(IDG) -- A little-known computer came out of MIT's Lincoln Laboratories in 1956 that wouldn't be well-remembered as the years went by, and yet its legacy reverberates more than 40 years later.

The TX-0 was the first programmable, general-purpose computer to dispense with vacuum tubes and rely on transistors and the first to test the use of a large magnetic core memory. More important, it was the first fully interactive computer available for wide use, one that inspired creativity that spawned some of the century's most important technological advances: computer graphics, Smalltalk, the Internet -- all were developed by TX-0 alumni.

"It helped train a generation of students in the hands-on, real-time interactive use of computers," says Wes Clark, who then was associate director of the Advanced Development Group at Lincoln Labs.

Clark worked on the project with Kenneth H. Olsen, who later would take ideas descended from the TX-0 and build the PDP-1, Digital Equipment Corp.'s first computer. Olsen was the engineer, Clark the system architect. Clark says he put together the TX-0's design over a single weekend.

"A simpler machine has probably not been built or used since," says Clark, who now works as a consultant to government and industry. "Utter simplicity was the overriding goal. It would have to be considered a RISC machine in current terms because it was so primitively simple."

What was truly special about the TX-0, from a user's perspective, was a light pen -- which Clark invented -- and display that let users enter data in real time and see a direct result. An early demonstration of the TX-0's interactive capabilities was an amusing program, developed by Doug Ross and John Ward and called Mouse Maze, which depicted a mouse going through a maze. When the mouse made a correct turn, it drank a martini; along the way, it became increasingly inebriated.

Mouse Maze was just a dim foreshadowing of the innovation to come after the TX-0 moved from Lincoln Labs to MIT's Research Laboratory of Electronics. From 1958 to the mid-'60s, students could sign up for an hour or two of time with the TX-0.

"This was very different than previous computers where you had a noisy room with a card reader and people just picked up their cards and left and had no interaction," recalls Jack Dennis, who oversaw the lab and wrote several programs that improved the TX-0's operation. Students would hang out in the lab, waiting for a turn at the console. "Everyone would look over each other's shoulders and could talk about what was going on. It was just a fun community," Dennis says.

Gordon Bell, now a senior member of Microsoft Corp.'s Bay Area Research Team and earlier the head of research and development at Digital, used the TX-0 to work on speech recognition, which led to a technique that's still a cornerstone of the technology.

"Anyone who used the TX-0 knew they wanted to work on interactive systems," Bell says. "In a funny way, I don't feel a hell of a lot different now than I did then. I think every morning when I wake up that there is something really wild and new and exciting to do that, in 50 years, will look just as wild."